The present invention relates generally to reducing drag resistance on marine vessels during travel.
The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefore.
During travel of a marine vessel within a body of water, flow of fluid relative to the solid external surfaces of the vessel hull is retarded by frictional contact imposing resistance to movement of the vessel dominated by frictional drag at high speeds. Many methods have been proposed to minimize such high speed drag resistance along the vessel hull, including emission of air bubbles, polymer injection, compliant coating and laminar boundary layer control by heating. While a degree of success may be achieved by such methods, various technical and practical problems are experienced therewith by reason of which high-speed friction drag reduction under efficient vessel propulsion operation remains a most challenging task. It is therefore an important object of the present invention to reduce drag resistance at high speeds without detracting from efficient operation of the marine vessel at all speeds of travel.
In accordance with the present invention, spaced water flow diverting wedges are mounted on the vertical sides of a marine vessel hull for deployment from retracted positions to protract flow diverting surfaces thereon of reduced length extending at a suitable angle from the smooth surfaced sides of the hull in the direction of travel so as to establish air ventilated cavities along the hull sides, within which the water is mixed with air, imposing drag resistance on the hull sides that is substantially less than that imposed directly by the water alone.